Connecting device for electron tubes



Nov. 17, 1953 o. STERNBECK CONNECTING DEVICE FOR ELECTRON TUBES 3 Sheets-Sheet 1 Filed June 2, 1950 Fig.1

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Filed June 2, 1950 5 Sheets-Sheet 2 1 culekewr N Fig.2

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. III/U ez'vbop O. 81: earn e ck Nov. 17, 1953 o. STERNBECK CONNECTING DEVICE FOR ELECT RON TUBES 5 Sheets-Sheet 3 Filed June 2, 1950 lzw ell/fir O. ernb 613k Patented Nov. 17, 1953 PATENT" QlafaSternbeck, Eriksvik, Saltsjobo, Sweden, asa

Signor to, Telefonaktiebolaget L,v M Ericsson,,

Stockholm, Sweden,

a company ofsweden l This inventio'n relatesto connecting'devices for electron tubes of the kind whichis, describedin thescopendingeapplication of'N. G. Backmark, Serial Nm 122,443,- filed October: 20,; ,1949, now Patent No; 2,591,997dated'April; 8, 1952:

The electron" tube utilized for the purpose of the inventionincludes, as appears from saidpat ent;a discharge-chamberpenetrated by a mag..-

netic: fieldand-containing' a cathode arranged centrally amonga plurality of electrodes situated in difireht directions around "and out from the cathode as seen in a plane perpendicular to the magneti mfieldr Saidelectrodes are by means of --"di'fferc-int connecting; devices arranged to be. giv e'n' -indiyidual voltages'di'fferent from those.

of the other electrodes.

If in' such atube the potentialiof one of the. electrodes is redu'ced1tozero; .it turns, out. that, currents flow isinitiated* to the next preceding electrode; counting in" thedirectionin. which a tangential velocity is imparted 'to the electrons due to the magnetic field; Figs. 1 and ,2, in said patent: It has been proved by practical experie ments -that this current substantially ,is derived from adimited part of thecathode which counting inathe above-mentioned direction, lies \imm e diately-behindthat electrode which has zero po,-. tential; Electrons may thus not be..emittedap,-. preciably- -from the larger part of the cathode sure. facesdue" to-infiuencefrom the ,spacecharge of the electron-"beam'; but only from. said. limited part 'of this surface, and the size of the effective emittingsurface will-be, dependent on the strength of the electric and magneticufields,

After the -electron beam has ,startedjfrom, said limited *cathode; sector situated, immediately be hind that electrode, which has, beenegivenl a zero voltageit passes thenpround the cathodeand is defie'cted due tothe curvature of the electric field 'in 'thewicinity of the zero, voltage electrode and'hitsfinallythe nextpreceding positive elecwhich havegreceived or delivered energy to the; surroundingsgwillalso.give rise to a dispersion ofj the's electronzbeam which inmany cases is extremely; unsnitableufrom a functional pointv of viewsaidznoiseincneaseswith the-path length which the velectrons have .totravelandis alsodependent; on the currentdensity of ithe electronibeam,and limits the maximum current that. may tbelallowed to flow in a tube of thisrkind This invention. has, for. its object tQ- I'GIIIQYG these and other, difficultieslarising in SuCh;;e1C-, tron tubes, said difficultieeliiniting;the;-current which maybe utilized.-practice;-for difierent connecting functions. According to. the, inve tion an ,increase'of the;maximum currentis Q tained, by, shortening, the p ath ofy the qelectrons; from the cathoderto, the electrode -,-t0 :Wllifihagbhiv current is desired.

In a device according to ithepatent rcitedabpva one can thus let some of-ithelradially arrange electrodes normally belataaanegatiilepo ential; or zero potential,,whilst the remaininggelectrodes n -l lat on flg i 2: cathode. Thus the, said emittingpathode sect will be closer to the active electrodes to Wh the current is desired, and a considerableisho ening of the path of the electrons isfilbtainedev also a considerable increasejnthe current i which; can beutilized in the tube;

In an. embodiment ofnthe 1 evice accordin teathe inventionthe different, electrodes surround: ing the cathodeare connected to-alternating volt ages ofnthe samecfrequency, which aregmntua phase-displaced, betweenan, electric angleaegrre c spending to, the geometric angle betweenfilec trodes of this kind arrangedadjacent each;,other;= Within the tube,

A similar application ,of; phase: voltage operation is already. known, but the-:tube referred 4303. in this connectionidifiersras limit/5 513111013111 r much from the voneutilized for the inventio has also a considerably smaller,focussing of '5 electron beam than ,whatjs obtainedraccoroi 13.. to this invention.

The invention willlbe described inqtheyfollowing in connection with, the embodiments of the shown in, the annexed drawing Fig. 1 in; th drawingshows, asectionof; an eleotllonzr-tube-i according, to the invention containingga-number; of control electrodes v and receiving electrodes Fig. 2 shows the current I,tocertain. lsp adeseanm plates as a function.of?the-phaseeposi-tiorr of; a;; polyphase,voltageconneotedytothegspadesc Fig shows current characteristics f for a-- number; of 1 plates, whereby the current. to these-electrodesds: by means ofjcertain connecting,elem ents-;.holsi:gV at a rather highland constant lvalufiad ring intervalyof, time which istconsiderabl reat In the embodiment according to Fig. 1 the electron tube, the envelope of which is indicated by H, contains a cathode K situated centrally in the tube and also a number of electrodes arranged round the same, including twelve plates P1-P12 and spades $21-$12 arranged between these plates and situated closer to the cathode. All these plates are, by means of leads through the envelope of the tube and through resistances r1r1z connected with the same voltage source Ea which is positive in relation to the cathode. To the spades S1S12 alternating voltages of the same frequency are supplied, but with a phase displacement of 1r/6 radians, each individually through resistances or impedances R3 etc. or directly at the points j1,f12. The zero point it for this polyphase system is connected to the cathode voltage source Ek- Under influence of this polphase voltage a continuously varying voltage distribution is obtained round the cathode, so that half the electrodes S1S12 get potentials O-Vu and the remaining ones the potentials +V0, if V0 indicates the maximum value of the supplied phase voltage. A comparison between Fig. 1 of the annexed drawing and the figures of said patent shows that a rather short electron path is obtained in the device according to this invention; in the figure this is indicated with dotted lines. The electron beam is accelerated by the electrodes of the positive sector in the tube, whilst the electrodes of the negative sector remain passive in this respect.

In Fig. 2 of the drawing the progress of the current to different electrodes during a part of a period of phase revolution is shown. As appears from the figure the current IP12 to the plate P12 equals the cathode current indicated by I1; during a part of the period comprising 7/6 radians. In the figure the currents Isl and Is12 to the spades S1 and S12 surrounding this plate are also indicated.

By connecting for instance resistances R3 etc. in Fig. 1 to the connections for the spades a form ofpositively acting stepping may be obtained. The electron beam may thereby give a maximum and comparatively constant current to the plates during a rather long period of time, whereafter an instantaneous stepping over to the next plate takes place as appears from Fig. 3, where curves of the current as a function of the phase position are shown. It appears from the figure that the currents IP12 etc. have their relatively constant maximum value during the greatest part of the period comprising 1r/6 radians, i. e. that practically the whole cathode current during this period flows to the intended electrode and that during the next period comprising 7r/6 radians it will be completely and instantaneously transferred to the next following plate.

In the embodiment of the invention shown in Figs. 4 and 5 each plate is divided into two completely separated parts, for instance the plates PEA, P613 and Pm, Pm. Of these the plates indicated with B are interconected by the battery EaB. The plates with index A are each provided with their individual connections. The electron beam will when directed into a box, for instance the one situated between the spades S1 and Sa, be branched into two parts one for each of the plates Pm and P11; situated in this box and the relation between the currents to these two electrodes is determined by the respective potentials of the same. The total current is hardly influenced by the voltages of the plates and a voltage increase of the plate P'na will for instance result in an increase of the current to the same frequencies.

plate and a corresponding decrease of the current to the plate Pm. In this manner a signal may evidently be sent for instance from the terminals I, 2 of the transformer pertaining to the plate Pm to the terminals 5, 6 of the common transformer for all the plates indicated by B, or else in the opposite direction. This may however be performed only during the time when the electron beam touches the plates Pm and P13. The transformers shown in the drawing may be replaced by other elements, for instance as is shown at the terminals l 1, I2. The spades of the device according to Fig. 4 are as in Fig. 1 connected to a polyphase voltage at the points f1f1z with or without interconnection of resistance elements. The cathode voltage is obtained from the battery Er, which like the other batteries Em and E113 is connected to the zero point in of the polyphase system.

An electron tube device according to the invention may advantageously be used for applications within the fields of multiplex telephony and multiplex telegraphy, for exploring connecting means and circuits and for producing multiple The rotating electron beam may also be phase modulated by variation of the potential of the cathode or, if a control grid is used, be amplitude modulated. Modulation may also be produced by super-position of modulation voltages on the spades and the plates.

The invention is not limited to the embodiments described above as it is obvious that different modifications of the same will fall within the scope of the same. It is for instance evident that it may be directly applicable to tubes having only one kind of electrodes surrounding the cathode, as are shown in Fig. 1 of the abovementioned application.

I claim:

Connecting device comprising an electron tube having an envelope within which are a number of radially mounted control electrodes, 2. cylindrical cathode for producing a ribbon shaped electron stream, said cathode being mounted centrally among said control electrodes, and a greater number of radially mounted receiving electrodes located in the compartments formed between adjacent control electrodes and mounted at a greater distance from the cathode surface than those parts of the control electrodes which lie nearest to said surface, means outside said envelope for producing a constant magnetic field penetrating the discharge space of said tube and the field lines of which are parallel to the axis of said cathode, means connecting one of the receiving electrodes in each of said compartments to a common positive voltage, means connecting the remaining receiving electrodes to positive voltages, and a polyphase alternating current source having each phase connected to one of said control electrodes for the purpose of directing said electron stream in sequence to said receiving electrodes.

OLAF STERNBECK.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,555,677 Leblanc Sept. 29, 1925 1,585,173 Simpson May 18, 1926 2,217,774 Skellett Oct. 15, 1940 2,432,608 Besch et al Dec. 16, 1947 2,591,997 Backmark Apr. 8,1952 e 

